The present invention relates generally to edge-lit luminaires and signage devices and in particular to edge-lit luminaires and signage devices having improved prismatic optical control.
Edge-lit luminaires are known. For example, U.S. Pat. No. 5,283,968 discloses an edge-lit luminaire including a housing containing a source of illumination arranged substantially adjacent to a display panel attached by one edge to the housing such that the panel extends from an opening in the housing. The display panel has an array of dots on at least part of one surface. The dots have a luminosity selected to be affected by illumination provided by the source located in the housing. As described, the display panel may consist of two sheets of transparent material, each of substantially identical dimensions at least one of which has an array of dots on a surface and sandwiching between them a sheet or card of opaque colored material. The sheet or card of opaque colored material is optional and the two sheets can be placed together without any intervening material.
U.S. Pat. No. 5,625,968 discloses an edge-lit illuminated display system one edge operable with a light source for illuminating the first and second surfaces. A matrix of dots on each of the surfaces is arranged to allow interaction of light between the surfaces. The dots can be applied to the transparent sheet by etching, painting, screen printing or other means of applying a medium to a transparent sheet. Alternatively, the matrix of dots may be applied to a transparent film that is then adhered to the transparent sheet.
A need exists for a mechanism for providing improved edge-lit luminaires. It is desirable to provide such improved edge-lit luminaires having panels controlling illumination using reflection to redirect rays traveling within the panel, from nearly parallel to the surfaces to nearly perpendicular to those surfaces. As used in the present specification and claims, edge-lit luminaires includes signage devices and all edge-lit panel applications including but not limited to, signs, displays, task and area lighting.
A principal object of the present invention is to provide a mechanism for providing improved edge-lit luminaires. Other important objects of the invention are to provide such improved edge-lit luminaires providing superior panel lighting performance substantially without negative effect and that overcome many of the disadvantages of prior art arrangements.
In brief, an edge-lit luminaire is provided. The edge-lit luminaire includes a panel formed of a transparent material. The panel includes first and second opposing surfaces. At least one edge light source is positioned proximate to the panel. A plurality of prismatic reflective/refractive elements are spaced apart on a predefined pattern on the second surface.
In accordance with features of the invention, the plurality of prismatic reflective/refractive elements have a predefined contour for accurate ray direction control. The predefined pattern on the second surface may include predefined gradient spacing and size variables of the prismatic reflective/refractive elements for providing uniform ray emission across the panel. The plurality of prismatic reflective/refractive elements have a predefined relative spacing of the prismatic reflective/refractive elements based upon a relative position to the light source. A predefined relative size of each of the prismatic reflective/refractive elements is based upon its